Endoscopic device

ABSTRACT

An endoscopic device that irradiates a plurality of illuminating light having different spectrums from each other onto a subject at a front edge of an endoscope inserting module and captures the subject to obtain an observation image The endoscopic device includes an illuminating module, an imaging module, a light intensity ratio control module, and a color tone correcting module. The illuminating module generates the plurality of illuminating light. The imaging module captures the subject and output an image signal of the observation image. The light intensity ratio control module controls the illuminating module to irradiate the plurality of illuminating light onto the subject with a set light intensity ratio by setting the light intensity ratio of the plurality of illuminating light. The color tone correcting module corrects the color tone to obtain the observation image with substantially the same color tone even though the light intensity ratio is changed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No.2011-174818 (filed on Aug. 10, 2011), the entire contents of which arehereby incorporated by reference.

BACKGROUND

1. Technical Field

The present invention relates to an endoscopic device.

2. Related Art

An endoscopic device that is used in the medical field performs a normalobservation that observes a subject image almost same as the observationby naked eyes by irradiating white light onto a subject in a biologicalbody as well as a narrow band observation that observes a subject imageby irradiating narrow band light having narrower wavelength band thanthe light irradiated during the normal observation. The narrow bandobservation observes the blood capillary or a micro pattern of asuperficial portion of the mucous membrane in the biological body with agood contrast and helps for an early detection of lesions.

The endoscopic device that is available for the narrow band observationpreferably changes the light intensities of the light emitted from thewhite light and the narrow band light depending on the observationscene. For example, the endoscopic device available for the narrow bandobservation increases the light intensity of the narrow band light inorder to easily observe the blood capillary of the superficial portionof the mucous membrane at the time of near view imaging and increasesthe light intensity of the white light at the time of distant viewimaging to resolve the insufficient amount of irradiated light. By doingthis, an observation image suitable for endoscopic diagnosis may beobtained. An endoscopic device that performs the above-mentioned narrowband observation is disclosed in JP-A-2011-10998.

However, when the white light and the narrow band light are irradiatedonto the subject while appropriately changing the emitted lightintensity ratio of the white light and the narrow band light, the colorshade of the illuminating light is changed. As a result, the color toneof the observation image is changed. If the color tone of theobservation image is changed, an operator may be bothered by a feelingof strangeness, which may influence an accurate endoscopic diagnosis.Further, if a predetermined image processing is performed to theobservation image, an intended image may not be obtained.

In the present invention, an endoscopic device can correct theobservation image so that the color tone of the observation image is notchanged even though the light intensity ratio of the illuminating lightis changed when each illuminating light is emitted from a plurality oflight sources that emit light having different spectrums, therebyperforming accurate endoscopic diagnosis by observing using illuminatinglight with an optimal light intensity ratio.

Summary of Invention

According to an aspect of the invention, an endoscopic device thatirradiates a plurality of illuminating light having different spectrumsfrom each other onto a subject at a front edge of an endoscope insertingmodule and captures the subject to obtain an observation image. Theendoscopic device includes an illuminating module, an imaging module, alight intensity ratio control module, and a color tone correctingmodule. The illuminating module generates the plurality of illuminatinglight. The imaging module captures the subject and output an imagesignal of the observation image. The light intensity ratio controlmodule controls the illuminating module to irradiate the plurality ofilluminating light onto the subject with a set light intensity ratio bysetting the light intensity ratio of the plurality of illuminating lightfor every observation image. The color tone correcting module correctsthe color tone of the image signal so as to obtain the observation imagewith substantially the same color tone even though the light intensityratio is changed.

When the illuminating light is emitted from a plurality of light sourcesthat emit light having different spectrums, the endoscopic deviceaccording to the present invention may correct the observation imagesuch that the color tone of the observation image is not changed eventhough the light intensity ratio of the illuminating light is changed.Therefore, the observation is performed with the illuminating light atan optimal light intensity ratio, so that it is possible to easilydiagnose an object to be observed and accurately perform diagnosis usingthe endoscope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an endoscopic device according to anexemplary embodiment of the present invention.

FIG. 2 is an external view illustrating a specific configuration exampleof the endoscopic device.

FIG. 3 is a graph illustrating spectral characteristics of emittedlight.

FIG. 4 is a flowchart of observational procedures in a body cavity bythe endoscopic device.

FIG. 5 is a graph illustrating distance table information representingthe relationship between a reflected light intensity and an estimateddistance L.

FIG. 6 is a graph illustrating distance and light intensity ratio tableinformation representing the relationship between an imaging distanceand an optimal light intensity ratio.

FIG. 7A is a graph illustrating a spectral intensity of the illuminatinglight when a light intensity ratio of LD1:LD2 is 1:4, and FIG. 7B is agraph illustrating a spectral intensity of the illuminating light whenthe light intensity ratio of LD1:LD2 is 4:1.

FIG. 8A is an explanatory diagram illustrating an observation image, andFIG. 8B is an explanatory diagram illustrating a state when a featuredimage region in the observation image is extracted.

FIGS. 9A and 9B are explanatory diagrams illustrating specificprocedures that calculate an optimal light intensity.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present invention will bedescribed with reference to the accompanying drawings.

FIG. 1 is a block diagram of the configuration of an endoscopic deviceaccording to an exemplary embodiment of the present invention, and FIG.2 is an external view illustrating a specific configuration example ofthe endoscopic device.

An endoscopic device 100, as shown in FIG. 1, includes an endoscope 11,a control device 13, a monitor 15, and an input module 17 such as akeyboard or a mouse that inputs information to the control device 13.The control device 13 is constituted by a light source device 19 thatoutputs illuminating light and a processor 21 that performs signalprocessing of an observation image.

The endoscope 11, as shown in FIG. 2, includes a main body operatingmodule 23, an inserting module 25 that is coupled to the main bodyoperating module 23 to be inserted into the subject (body cavity), and auniversal cord 27 that is connected to the main body operating module23. The front edge of the universal cord 27 is provided with a lightguide (LG) connector 29B that is connected to the light source device 19and a video connector 29A that is connected to the processor 21.

Various operating buttons 31 including a button for suctioning, airsupplying, and water supplying at the front edge side of the insertingmodule 25, a shutter button at the time of imaging, a mode switchingbutton that switches an observation mode, and a confirmation button 30for confirming a lesion area at the time of endoscopic diagnosis, whichwill be described below, are provided together in the main bodyoperating module 23 of the endoscope 11. A pair of angle knobs 33 isprovided in the main body operating module 23.

The inserting module 25 is constituted by a flexible part 35, acurvature part 37, and a front edge part (an endoscope front edge part)39 in order from the main body operating module 23 side. The curvaturepart 37 is remotely curved by rotating the angle knob 33 of the mainbody operating module 23, which allows the front edge part 39 to beoriented in a desired direction.

At the front edge part 39 of the endoscope, as shown in FIG. 1, anobservation window 41 of an imaging optical system and illuminationwindows 43A, 43B of an illuminating optical system are arranged. Each ofthe illumination windows 43A, 43B emits illuminating light onto thesubject. The reflected light from the subject is detected (captured) byan image pickup device 45 through the observation window 41. An imagesignal output from the image pickup device 45 is digitalized by ananalogue/digital (A/D) converting module 47 and then, the image signalis input to the processor 21 through a signal cable 49 to be subjectedto an appropriate image processing thereon, and the image signal isdisplayed on the monitor 15 connected to the processor 21.

The imaging optical system includes the image pickup device 45 such as acharge coupled device (CCD) type image sensor or a complementary metaloxide semiconductor (CMOS) type image sensor and an optical member 51such as a lens that forms the observation image onto the image pickupdevice 45. The image pickup device 45 may include a color filter ofcomplementary color such as CMY or CMYG in addition to a color filter ofRGB primary color. An imaging condition of the image pickup device 45such as a shutter speed or an iris diaphragm is set by an imagingcontrol module 53.

The illuminating optical system includes the light source device 19, apair of optical fibers 55A, 55B connected to the light source device 19through the light guide connector 29B, and wavelength converting members57A, 57B which are disposed at light emitting ends of the optical fibers55A, 55B, respectively. The light source device 19 includes laser lightsources LD1, LD2 which are semiconductor light emitting elements, alight source control module 59 that controls to drive the laser lightsources LD1, LD2, a combiner 61 that combines the light emitted from thelaser light sources LD1, LD2, and a coupler 63 that divides the lightemitted from the combiner 61 into the optical fibers 55A, 55B.

The laser light source LD1 is a blue light emitting semiconductor laserhaving a central wavelength of 445 nm and combines the blue laser lightand fluorescence obtained by exciting the wavelength converting members57A, 57B to generate white illuminating light. The laser light sourceLD2 is a violet light emitting semiconductor laser having a centralwavelength of 405 nm. For example, a broad area type InGaN-based laserdiode may be used as the laser light sources. If the central wavelengthof the emitted light is in a range between 370 nm and 470 nm, the laserlight source LD2 allows good narrow band observation in which the bloodcapillary or a micro pattern of a superficial portion of the mucousmembrane is emphasized.

A band width of wavelength of each of the laser light sources LD1 andLD2 at half maximum is equal to or less than 60 nm, preferably equal toor less than 40 nm, more preferably equal to or less than 20 nm. In viewof the light intensity, the band width at half maximum is preferablyequal to or less than 10 nm.

The light source control module 59 controls the light intensity of eachof the laser light sources LD1, LD2 based on the command of the controlmodule 71 of the processor 21. The emitted light passes through theoptical fibers 55A, 55B to be guided to the endoscope front edge part 39and then is irradiated on the wavelength converting members 57A, 57B. Asdescribed above, the light source control module 59 controls the lightemitted from the laser light sources LD1, LD2 so as to simultaneouslyemit light from the illumination windows 43A, 43B with an arbitrarylight intensity at an arbitrary timing.

The wavelength converting members 57A, 57B are configured to include aplurality kinds of fluorescent substances (for example, YAG fluorescenceor fluorescence including, for example, BAM (BaMgAl₁₀O₃₇)) that absorb apart of a blue laser light emitted from the laser light source LD1 andemits green to yellow color light. By the wavelength converting members57A, 57B, as the spectral characteristics of the emitted light is shownin FIG. 3, the blue laser light of the laser light source LD1 and thegreen to yellow excited light obtained by the wavelength conversion ofthe blue laser light are composited to generate white light having highcolor rendering property that is represented by a profile S1.

With respect to the light emitted from the laser light source LD2, theabsorption of the fluorescence is low and the wavelength convertingefficiency by the wavelength converting members 57A, 57B is low.Therefore, the intensity of the fluorescence generated by the laserlight source LD2 is insufficient as compared with the laser light sourceLD1. As shown in a profile S2 of FIG. 3, the light emitted from thelaser light source LD2 is mostly narrow band light having a centralwavelength of 405 nm, which is substantially shorter than the whitelight, and having a narrower wavelength band than the white light.

With the above-mentioned configuration, the laser light emitted from thelaser light sources LD1, LD2 are guided to the endoscope front edge part39 by the optical fibers 55A, 55B so that the white light and violetnarrow band light are emitted from both illumination windows 43A, 43B ofthe endoscope front edge part 39 with an arbitrary light intensity ratiobased on the command from the control module 71. As described above, thelaser light from both laser light sources LD1, LD2 is irradiated ontothe subject through the same fluorescent substance at the illuminationwindows 43A, 43B, so that the laser light is irradiated onto the subjectso as to be substantially equally spread from the same portion.Therefore, there is no difference in the illumination range by theemitted light or difference in the intensity distribution, which allowsobtaining a good observation image.

Specifically, the control module 71 outputs a control signal to thelight source control module 59 and the light source control module 59outputs a driving signal, which turns ON/OFF the laser light sourcesLD1, LD2 by the input control signal.

The laser light sources LD1, LD2 emit light with a light intensity basedon the input driving signal. Therefore, the intensity or light intensityratio (color shade) of the light emitted from the illumination windows43A, 43B is adjusted. Accordingly, the control module 71 functions as alight intensity control module that changes the light intensity ratio ofthe white light and the narrow band light of the illuminating light.

The processor 21 includes the control module 71, a frame memory 73 thatstores the picked up image signal, an imaging distance estimating module75 that estimates an imaging distance to the subject based on thebrightness information of the image signal, an optimal light intensityratio setting module 77 that sets the light intensity ratio suitable forobservation, and a setting information storing module 79 that storesvarious information for setting the optimal light intensity ratio. Theprocessor 21 further includes a color tone correcting module 83 thatcorrects the color tone of the image signal and an image processingmodule 85.

With the above configuration of the control device 13, the controlmodule 71 sets the light intensity ratio of the light emitted from thelaser light sources LD1, LD2 which is optimal for the observation imagewith respect to the image signal of the observation image including, forexample, the lesion area. Therefore, the observation image may be alwayssuitable for the endoscopic diagnosis.

Hereinafter, the setting of the light intensity ratio will be describedwith a specific observation procedure.

FIG. 4 illustrates a flowchart of an observation procedure in a bodycavity by the endoscopic device 100. In the observation procedureillustrated as an example, the operator of the endoscopic device 100sets the light intensity ratio of the light emitted from the laser lightsources LD1, LD2 to a standard light intensity ratio for endoscopy (S1).The light intensity ratio may be manually or automatically set, forexample, input from the input module 17 connected to the control device13 or set by referring to the standard light intensity ratio stored inthe setting information storing module 79 in advance.

The standard light intensity ratio is a ratio when the laser lightsource LD2 is turned OFF and only the laser light source LD1 (445 nm) isturned ON, that is, LD1 (λ₄₄₅):LD2 (λ₄₀₅)=100:0, which becomesilluminating light for normal observation by the white light.

The operator starts the endoscopy by inserting the endoscope insertingmodule 25 to which the white light from the front edge is emitted intothe subject (S2). The control module 71 outputs the observation image ofthe inside of the subject to the monitor 15 so as to display theobservation image on the monitor 15. The operator identifies the lesionarea from the displayed observation image. If there is a lesion area(S3), the operator presses the confirmation button 30 (see, for example,FIGS. 1 and 2) of the main body operating module 23.

The control module 71 receives a signal that the confirmation button30is pressed and estimates the imaging distance to the subject based onthe information of AE value which is an imaging condition of theobservation image and the information of the illuminating lightintensity that is set by the light source control module 59 (S4). The AEvalue and the distance table information, which indicates therelationship between the estimated distance L and the reflection lightintensity defined by the illuminating light intensity, are prepared inadvance as shown in FIG. 5, and then the imaging distance is estimatedby referring to the distance table information. The distance tableinformation is prepared for every AE value (for example, shutter speed,iris diaphragm, and brightness) at the time of imaging and imagingcondition of the illuminating light intensity, and the distance tableinformation is stored in the setting information storing module 79. Thecontrol module 71 selectively refers to the distance table informationcorresponding to the imaging condition of the observation image toestimate the imaging distance L.

Next, the control module 71 calculates the optimal light intensity ratio[LD1 (λ₄₄₅): LD2 (λ₄₀₅)] for the estimated imaging distance L. Thedistance and light intensity ratio table information, as shown in FIG.6, is prepared in advance, which indicates the relationship between theimaging distance and the optimal light intensity ratio. The optimallight intensity ratio is set by referring to the distance and lightintensity ratio table information. The distance and light intensityratio table information is stored in the setting information storingmodule 79 so as to be referred by the control module 71 as needed. Thecontrol module 71 refers to the distance and light intensity ratio tableinformation to set the emitted light intensity of the LD2 to be largerthan the light intensity of the LD1 so that the imaging distance becomesshorter to emphasize the blood capillary of the superficial portion ofthe mucous membrane. As the imaging distance becomes longer, the emittedlight intensity of the LD1 is set to be larger than the light intensityof the LD2 so as to be the illuminating light having high illuminationintensity to ensure the brightness of the long distance view.Alternatively, in accordance with the imaging distance, the lightintensity ratio for the short distance view in which the emitted lightintensity of the LD2 is larger than the light intensity of the LD1 andthe light intensity ratio for the long distance view in which theemitted light intensity of the LD1 is larger than the light intensity ofthe LD2 may be switched to control the light intensity ratio in twostages.

As described above, the control module 71 estimates the imaging distancefrom the observation image and turns ON/OFF the laser light sources LD1,LD2 with an optimal light intensity ratio in accordance with theestimated imaging distance, and therefore, the light intensity ratio isautomatically changed so as to allow the operator to easily observe thesubject.

However, the emitted light of the laser light source LD1 is finallyirradiated onto the subject as the white light and the emitted light ofthe laser light source LD2 is irradiated onto the subject as the violetlight. Accordingly, if the light intensity ratio of the emitted light ofthe laser light sources LD1, LD2 is changed, the color tone of theilluminating light is changed. FIG. 7A is a graph illustrating aspectral intensity of illuminating light when a light intensity ratio ofLD1:LD2 is 1:4, and FIG. 7B is a graph illustrating a spectral intensityof illuminating light when a light intensity ratio of LD1:LD2 is 4:1. Ifthe light intensity of the LD2 is increased as compared with the lightintensity of the LD1, the illuminating light becomes a bluish light andas a result, the color tone of the observation image is changed inaccordance with the light intensity ratio.

Therefore, the color tone of the observation image is corrected inaccordance with the color shade of the illuminating light that ischanged by the set light intensity ratio (S6), so that the observationimage is not affected by the change in the color shade of theilluminating light. The control module 71 outputs the information of thelight intensity ratio set by the optimal light intensity ratio settingmodule 77 to the color tone correcting module 83 together with the imagesignal of the observation image. The color tone correcting table forevery light intensity ratio is prepared in the setting informationstoring module 79, and the color tone correcting module 83 selectivelyrefers to the color tone correcting table corresponding to the set lightintensity ratio to correct the change in the color tone of the image(increase in the blue color) to be eliminated.

The color tone correcting table, for example, may be represented as acorrecting matrix that corrects R, G, and B values using a matrix foreach of the pixels of the observation image. If the correcting matrix isA, brightness values R′, G′, and B′ of the pixels after correcting arerepresented by Equation (1).

$\begin{matrix}{{{Equation}\mspace{14mu} 1}\mspace{610mu}} & \; \\{\begin{pmatrix}R^{\prime} \\G^{\prime} \\B^{\prime}\end{pmatrix} = {{A\begin{pmatrix}\begin{matrix}R \\G\end{matrix} \\B\end{pmatrix}} = {\begin{pmatrix}a_{11} & a_{12} & a_{13} \\a_{21} & a_{22} & a_{23} \\a_{31} & a_{32} & a_{33}\end{pmatrix}\begin{pmatrix}R \\G \\B\end{pmatrix}}}} & (1)\end{matrix}$

A coefficient a_(ij) of the correcting matrix A is set to eliminate thechange in the color shade of the illuminating light by the change in thelight intensity ratio, so that a plurality kinds of correction matrixesA corresponding to the plurality kinds of light intensity ratios areprepared in advance. The information of the correcting matrixes isstored in the setting information storing module 79. The control module71 uses the selected correcting matrix A to correct the RGB brightnessvalues of each of the pixels of the observation image and outputs thecorrected image to be obtained on the monitor 15.

The control module 71 continues the above procedures until theobservation of the lesion area is completed (S7). Further, when anotherlesion area is found, the above procedures S4 to S6 are repeated. Theprocedures by the above sequence are performed until the observation iscompleted (S8).

As described above, even though the light intensity ratio of theilluminating light is changed by setting an optimal light intensityratio, the color tone of the observation image is corrected inaccordance with the set light intensity ratio. Therefore, even thoughany light intensity ratio is set, the image information may always beobtained as the observation image under constant color shade of theilluminating light. Accordingly, it is possible to always performaccurate endoscopic diagnosis. Further, various image processing thatare subjected to the captured image, for example, a spectral endoscopeimage processing that creates a new observation image from the imageintensity of a specific wavelength set (three primary colors),enhancement processing of various specific portions, or pseudo colorprocessing is not affected by the change in the color shade of theilluminating light caused by changing the light intensity ratio of thelaser light sources LD1, LD2.

Next, another example of endoscopic diagnosis by the above-mentionedendoscopic device will be described.

The endoscopic device with the present configuration, as shown in FIG.1, newly includes a featured image region extracting module 81 thatextracts a specific featured image region from the image signal.

FIG. 8A is an example of an observation image and shows an aspect thatthe blood capillary of a superficial portion of the mucous membrane inthe image is displayed as a micro dot pattern. The dot pattern 91 thatis the information of the blood capillary is brown as compared with thecolor of the surrounding pixels. Therefore, as shown in FIG. 8B, thefeatured image region 93 that is a blood capillary region may beselectively extracted by performing the image processing based on thecolor change information with respect to the surrounding pixels by thefeatured image region extracting module 81.

The control module 71 appropriately sets the light intensity ratio ofthe illuminating light so that the extracted featured image region 93has a high S/N.

In order to provide an optimal light intensity ratio for the featuredimage region 93, the optimal light intensity ratio setting module 77sets the optimal light intensity ratio by referring to the lightintensity ratio for emphasizing the blood vessel stored in the settinginformation storing module 79 in advance. The light intensity ratio foremphasizing the blood vessel is a light intensity ratio in which thatthe intensity of the light emitted from the LD2 is set to be larger thanthe LD1 in order to emphasize the blood vessel of a superficial portionof the mucous membrane.

The control module 71 controls the light source control module 59 tohave a set optimal light intensity ratio to emit desired illuminatinglight from the laser light sources LD1, LD2. With respect to theobservation image output from the image pickup element 45, the colortone correcting module 83selects a correcting matrix, as describedabove, to correct the RGB signal value using the selected correctingmatrix.

As described, by irradiating the illuminating light with an optimallight intensity ratio for an area specified to the featured image region93, an observation image that easily diagnoses the object to be observedis obtained. Further, the change in the color tone occurring in theobservation image caused by the change in the light intensity ratio iscorrected to obtain the same observation image as the illuminated by theilluminating light with the same color tone. Therefore, it is possibleto increase the accuracy of the endoscopic diagnosis.

In the above exemplary embodiment, even though the featured image region93 is extracted based on the color change in the observation image,especially, based on the information of a R signal value, a G signalvalue, and a B signal value, the featured image region including theblood capillary or micro pattern is simply extracted by calculating aratio of the B signal value and the G signal value to which the bloodvessel or the micro pattern of a superficial portion of the mucousmembrane is emphasized to be displayed regardless of the information ofthe color signal. Further, other than the information of the colorchange or the change of the ratio of the B and G signals, for example,using a fact that the blood capillary is represented in the image as amicro pattern, the high frequency component may be extracted from theobservation image to determine the featured image region 93. The highfrequency component region, for example, is obtained by extracting apredetermined frequency component from a spectrum image, which isobtained by performing the two-dimensional Fourier transformation, usinga mask processing and then performing inverse Fourier transformation onthe extract result.

Next, a modified example that calculates the optimal light intensityratio of the laser light sources LD1, LD2 from the information of theobservation image without using the distance and light intensity ratiotable information or the setting value such as the light intensity ratiofor emphasizing the blood vessel, will be described.

If the light intensity ratio of the light emitted from the laser lightsources LD1, LD2 is changed, the brightness contrast of the observationimage is changed. Therefore, while measuring the light intensity ratiowhere the brightness contrast is at the maximum so as to be found, thelight intensity ratio having the maximum brightness contrast isultimately determined.

Explanatory diagrams illustrating specific procedures that calculate anoptimal light intensity ratio are illustrated in FIGS. 9A and 9B. First,all of three kinds of light intensity ratios of an arbitrary lightintensity ratio α, a light intensity ratio α-δ in which a predeterminedamount is subtracted from the arbitrary light intensity ratio α, and alight intensity ratio α+δ in which the predetermined amount is added tothe arbitrary light intensity ratio a are determined and theilluminating light is sequentially set with the light intensity ratios.In this case, the observation images by the illuminating light set withthe light intensity ratios are captured to calculate the brightnesscontrast of three captured observation images.

As shown in FIG. 9A, when the brightness contrast is increased in adirection where the light intensity ratio is reduced from the lightintensity ratio α, the light intensity ratio is controlled to be reducedby the predetermined amount. In contrast, when the brightness contrastis increased in a direction where the light intensity ratio is increasedfrom the light intensity ratio α, the light intensity ratio iscontrolled to be increased by the predetermined amount. Further, withrespect to the reduced or increased light intensity ratio, theabove-mentioned procedures are repeated.

By doing this, as shown in FIG. 9B, since the light intensity ratioα_(B) in which the brightness contrast is the maximum is obtained, thelight intensity ratio α_(B) is set as the optimal light intensity ratio.The control module 71 obtains the observation image irradiated with theset optimal light intensity ratio and outputs the information of the setoptimal light intensity ratio to the color tone correcting module 83together with the image signal of the observation image. The color tonecorrecting module 83, as described above, corrects the change in thecolor tone of the observation image to be eliminated by selectivelyreferring to the color tone correction table corresponding to the setlight intensity ratio.

As described above, the present invention is not limited to the aboveexemplary embodiments, but the combinations of the components of theexemplary embodiments or change or application based on the descriptionof the specification or the known technology are also included in thepresent invention.

For example, even though laser light sources having different lightemitting wavelength are used as a light source, the combination of awhite light source such as a xenon lamp or a halogen lamp and asemiconductor light source such as a light emitting diode or a laserlight source that emits a specific wavelength light, may be used.

As described above, the present specification discloses the followingaspects.

(1) An endoscopic device that irradiates a plurality of illuminatinglight having different spectrums from each other onto a subject at afront edge of an endoscope inserting module and captures the subject toobtain an observation image, including:

an illuminating module configured to generate the plurality ofilluminating light;

an imaging module configured to capture the subject and output an imagesignal of the observation image;

a light intensity ratio control module configured to control theilluminating module so as to irradiate the plurality of illuminatinglight onto the subject with a set light intensity ratio by setting thelight intensity ratio of the plurality of illuminating light for everyobservation image; and

a color tone correcting module configured to correct the color tone ofthe image signal so as to obtain the observation image withsubstantially the same color tone even though the light intensity ratiois changed.

According to the endoscopic device, when the illuminating light isemitted from the plurality of light sources that emit light havingdifferent spectrums, even though the light intensity ratio of theilluminating light is changed, the observation image may be correctedwithout changing the color tone of the observation image. Therefore, thesubject may be observed with the illuminating light at an optimal lightintensity ratio, and accurate endoscope diagnosis may be achieved.

(2) The endoscopic device of (1), wherein the light intensity ratiocontrol module includes an imaging distance estimating module configuredto estimate an imaging distance from the front edge of the endoscopeinserting module to the subject and sets the light intensity ratio basedon the imaging distance estimated by the imaging distance estimatingmodule.

According to the endoscopic device, the light intensity ratio may beappropriately changed at the time of near view imaging having shortimaging distance and at the time of distant view imaging having a longimaging distance. Therefore, for example, the near view imaging that isrequired to perform the narrow band imaging and the distant view imagingwhere the distance portion is tend to be dark are performed by theilluminating light at an optimal light intensity ratio so that the colortone of the observation image is not varied in accordance with thedistance.

(3) The endoscopic device of (2), wherein the imaging distanceestimating module calculates the imaging distance based on an AE valueset in the imaging module and the entire light intensity of theplurality of illuminating light that is irradiated on the subject.

According to the endoscopic device, the imaging distance may be simplyand precisely obtained from the information of the AE value and theinformation of the illuminating light intensity.

(4) The endoscopic device of any one of (1) to (3), wherein the colortone correcting module includes a correction information storing modulein which correction information for correcting the color tone of theimage signal corresponding to the light intensity ratio set by the lightintensity ratio control module is stored in advance and corrects thecolor tone corresponding to the light intensity ratio by referring tothe correction information of the correction information storing module.

According to the endoscopic device, the color tone correcting modulecorrects the color tone of the image signal using the correctioninformation of the correction information storing module, to simplyeliminate the change in the color tone of the observation image due tothe set light intensity ratio.

(5) The endoscopic device of (4), wherein the correction information isa color tone correcting table that corrects R, G, and B values forpixels of the observation image using a matrix.

According to the endoscopic device, the color signal values of theobservation image is corrected using matrix correction with high degreeof freedom of a design so that various color tone adjustment may beeasily applied.

(6) The endoscopic device of any one of (1) to (5), further comprising:

a featured image region extracting module configured to extract afeatured image region included in the observation image from the imagesignal of the observation image,

wherein the light intensity ratio control module sets the lightintensity ratio so that the featured image region is suitable for theobservation.

According to the endoscopic device, the featured image region may beobserved by the illuminating light having an optimal light intensityratio, and thus the change in the color tone of the observation image isnot caused by the change in the light intensity ratio. Therefore, thefeatured image region may be precisely diagnosed.

(7) The endoscopic device of (6), wherein the featured image region hasdifferent color tone from the other region in the observation image.

According to the endoscopic device, an image region having differentcolor from the surround pixel may be set as the featured image region.

(8) The endoscopic device of (7), wherein the featured image region is ablood capillary region of a superficial portion of the mucous membraneof the subject.

According to the endoscopic device, an image region which is turned inbrown due to lots of the locally generated blood capillaries of asuperficial portion of the mucous membrane may be set as the featuredimage region.

(9) The endoscopic device of (8), wherein the light intensity ratiocontrol module sets the light intensity ratio by referring to the lightintensity ratio for blood emphasis prepared in advance.

According to the endoscopic device, the blood capillary of a superficialportion of the mucous membrane may be observed with a standard degree ofemphasis.

(10) The endoscopic device of (6), wherein the featured image regionincludes a high frequency component of a micro pattern of thesuperficial portion of the mucous membrane.

According to the endoscope device, for example, an image region having ahigh frequency component such as a region in which lots of the bloodcapillaries or micro patterns of a superficial portion of the mucousmembrane locally appear is set as the featured image region.

(11) The endoscopic device of any one of (6) to (10), wherein thefeatured image region extracting module extracts the featured imageregion based on an R signal value, a G signal value, and a B signalvalue of the image signal.

According to the endoscopic device, the featured image region isextracted based on the respective color signal values of the capturedimage signal. Therefore, various extracting algorism may be used, whichgives lots of options for extract processing.

(12) The endoscopic device of any one of (6) to (10), wherein thefeatured image region extracting module extracts the featured imageregion based on a ratio of the B signal value and the G signal value ofthe image signal.

According to the endoscopic device, by calculating a ratio of the Bsignal value and the G signal value displayed by emphasizing the bloodcapillary or a micro pattern of a superficial portion of the mucousmembrane, the location of the blood capillary or a micro pattern of thesuperficial portion of the mucous membrane is determined. Therefore, ifthe ratio of the B signal value and the G signal value is used, thefeatured image region may be simply extracted.

(13) The endoscopic device of any one of (6) to (10), wherein thefeatured image region extracting module obtains a high frequencycomponent extracted image obtained by extracting a predetermined highfrequency component by performing a mask processing onto the spectrumimage obtained by performing the two-dimensional Fourier transformationon the image signal and performing an inverse Fourier transformation onthe high frequency component extracted image to extract the featuredimage region including only the predetermined high frequency component.

According to the endoscopic device, the high frequency component may beprecisely detected.

(14) The endoscopic device of any one of (1) to (13), wherein theplurality of illuminating light include a first illuminating light and asecond illuminating light having a wavelength band narrower than thefirst illuminating light, and

the illuminating module includes a first light source which is a lightsource of the first illuminating light, a second light source that is alight source of the second illuminating light, and a wavelengthconverting member that converts the wavelength of light emitted from thefirst light source to make the light as first illuminating light.

According to the endoscopic device, the first illuminating light havinga broad spectrum is obtained and the color rendering properties isimproved.

(15) The endoscopic device of (14), wherein the wavelength convertingmember is provided to simultaneously covert the wavelength of the lightemitted from the first light source to use as the first illuminatinglight and convert the wavelength of the light emitted from the secondlight source to use as the second illuminating light, and the wavelengthconversion efficiency of the wavelength converting member for the lightemitted from the second light source is smaller than the wavelengthconversion efficiency for the light emitted from the first light source.

According to the endoscopic device, the optical system is made simpleand the light emitted from the second light source may be added withoutlargely affecting the first illuminating light by the emitted light ofthe first light source.

(16) The endoscopic device of (14) or (15), wherein the first lightsource is a blue light emitting light source, the first illuminatinglight is white light, and the second light source emits light having acentral wavelength in the range between 370 nm and 470 nm.

According to the endoscopic device, the subject is illuminated byvisible light having a short wavelength from the second light source toobtain an observation image in which the blood capillary or the micropattern of the superficial portion of the mucous membrane is emphasized,which increases the accuracy of the diagnosis.

1. An endoscopic device that irradiates a plurality of illuminatinglight having different spectrums from each other onto a subject at afront edge of an endoscope inserting module and captures the subject toobtain an observation image, comprising: an illuminating module thatgenerates the plurality of illuminating light; an imaging module thatcaptures the subject and output an image signal of the observationimage; a light intensity ratio control module that controls theilluminating module to irradiate the plurality of illuminating lightonto the subject with a set light intensity ratio by setting the lightintensity ratio of the plurality of illuminating light for everyobservation image; and a color tone correcting module that corrects thecolor tone of the image signal so as to obtain the observation imagewith substantially the same color tone even though the light intensityratio is changed.
 2. The endoscopic device according to claim 1, whereinthe light intensity ratio control module includes an imaging distanceestimating module configured to estimate an imaging distance from thefront edge of the endoscope inserting module to the subject and sets thelight intensity ratio based on the imaging distance estimated by theimaging distance estimating module.
 3. The endoscopic device accordingto claim 2, wherein the imaging distance estimating module calculatesthe imaging distance based on an AE value set at the imaging module andthe entire light intensity of the plurality of illuminating light thatis irradiated on the subject.
 4. The endoscopic device according toclaim 1, wherein the color tone correcting module includes a correctioninformation storing module in which correction information forcorrecting the color tone of the image signal corresponding to the lightintensity ratio set by the light intensity ratio control module isstored and corrects the color tone corresponding to the light intensityratio by referring to the correction information stored in thecorrection information storing module.
 5. The endoscopic deviceaccording to claim 4, wherein the correction information is a color tonecorrecting table that corrects R, G, and B values for pixels of theobservation image using a matrix.
 6. The endoscopic device according toclaim 1, further comprising: a featured image region extracting modulethat extracts a featured image region included in the observation imagefrom the image signal of the observation image, wherein the lightintensity ratio control module sets the light intensity ratio so thatthe featured image region is suitable for the observation.
 7. Theendoscopic device according to claim 6, wherein the featured imageregion has different color tone from the other region in the observationimage.
 8. The endoscopic device according to claim 7, wherein thefeatured image region is a blood capillary region of a superficialportion of the mucous membrane of the subject.
 9. The endoscopic deviceaccording to claim 8, wherein the light intensity ratio control modulesets the light intensity ratio by referring to the light intensity ratiofor blood emphasis prepared in advance.
 10. The endoscopic deviceaccording to claim 6, wherein the featured image region includes a highfrequency component which is a micro pattern of the superficial portionof the mucous membrane.
 11. The endoscopic device according to claim 6,wherein the featured image region extracting module extracts thefeatured image region based on an R signal value, a G signal value, anda B signal value of the image signal.
 12. The endoscopic deviceaccording to claim 6, wherein the featured image region extractingmodule extracts the featured image region based on a ratio of the Bsignal value and the G signal value of the image signal.
 13. Theendoscopic device according to claim 6, wherein the featured imageregion extracting module obtains a high frequency component extractedimage obtained by extracting a predetermined high frequency component byperforming a mask processing onto the spectrum image obtained byperforming the two-dimensional Fourier transformation on the imagesignal and performing an inverse Fourier transformation on the highfrequency component extracted image to extract the featured image regionincluding only the predetermined high frequency component.
 14. Theendoscopic device according to claim 1, wherein the plurality ofilluminating light include a first illuminating light and a secondilluminating light having a wavelength band narrower than the firstilluminating light, and the illuminating module includes a first lightsource which is a light source of the first illuminating light, a secondlight source that is a light source of the second illuminating light,and a wavelength converting member that converts the wavelength of lightemitted from the first light source to make the light as firstilluminating light.
 15. The endoscopic device according to claim 14,wherein the wavelength converting member is provided to simultaneouslycovert the wavelength of the light emitted from the first light sourceto use as the first illuminating light and convert the wavelength of thelight emitted from the second light source to use as the secondilluminating light, and the wavelength conversion efficiency of thewavelength converting member for the light emitted from the second lightsource is smaller than the wavelength conversion efficiency for thelight emitted from the first light source.
 16. The endoscopic deviceaccording to claim 14, wherein the first light source is a blue lightemitting light source, the first illuminating light is white light, andthe second light source emits light having a central wavelength in therange between 370 nm and 470 nm.
 17. The endoscopic device according toclaim 15, wherein the first light source is a blue light emitting lightsource, the first illuminating light is white light, and the secondlight source emits light having a central wavelength in the rangebetween 370 nm and 470 nm.